The present invention relates to an integrated circuit device, an electronic instrument, and the like.
In order to implement a ubiquitous network society, a sensor network that is formed by connecting a plurality of sensors through a network and acquires information from each sensor to comprehensively determine the situation is necessary. Such a sensor network utilizes various sensors such as a temperature sensor, a smoke sensor, an optical sensor, a human detection sensor, a pressure sensor, a biosensor, and a gyrosensor. A sensor detection signal varies in amplitude, DC offset, frequency band, and the like corresponding to the type of sensor.
Since the sensor detection signal (sensor signal) is an analog signal, the analog sensor detection signal must be converted into digital data in order to analyze and determine information using a CPU or the like. For example, JP-A-2007-117586 and JP-A-2007-285745 disclose A/D converters that convert an analog detection signal output from a sensor into digital data.
However, an integrated circuit device (IC) that includes such an A/D converter has been generally developed as a sensor-specific integrated circuit device. Therefore, when a new sensor has been developed, an integrated circuit device for the new sensor must be developed and produced by way of trial. This process is very expensive. In this case, a general-purpose integrated circuit device may be used. However, since a sensor detection signal varies in amplitude and DC offset corresponding to the type of sensor, it is substantially impossible to deal with a new sensor using a general-purpose integrated circuit device. Therefore, the user cannot easily produce an integrated circuit device for various sensors by way of trial.
In order to deal with various sensors, it is desirable to arbitrarily adjust the offset and the gain of a sensor detection signal that varies in amplitude and DC offset corresponding to the type of sensor.
However, when implementing such an offset adjustment and the like using a single-stage amplifier and a single-stage D/A converter provided corresponding to the single-stage amplifier, an increase in the size of the D/A converter, a decrease in response speed, or the like may occur.